In recent years, CDNs have become increasingly relevant, particularly in the field of the internet. Typically, CDNs directly peer with a large number of ISP and are responsible for a large portion of the internet and the inter-domain traffic. This situation is described and summarized, for example, in Labovitz C. et al.: “Internet Inter-Domain Traffic”. SIGCOMM'10, New Delhi, India. Aug. 30, 2010-Sep. 3, 2010. CDNs may have different and conflicting objectives compared to those of ISPs. The way a CDN selects hosts to deliver content to clients is usually based on a combination of performance and cost metrics. Moreover, the ISP is typically not involved in the host selection process. This can lead to a lose-lose situation as the clients' experience may not be satisfactory and the ISP loses the control of the traffic that flows within its network. For example, the decision of a CDN is based on internet protocol (IP) addresses of a domain name system (DNS) resolver that forwards a request to the CDN and not on the IP of the client. The IP addresses and thus the location of the client or end-user are not known to the CDN in conventional implementations.
In order to improve this situation to reach a win-win situation, theoretic concepts of collaboration between ISP and CDN have been introduced. For example, game-theoretic studies such as described in Wenjie J. et al.: “Cooperative Content Distribution and Traffic Engineering in an ISP Network”. SIGMETRICS/Performance'09, pp. 75-86, Seattle, Wash., USA. Jun. 15, 2009-Jun. 19, 2009, and in DiPalantino D. et al.: “Traffic Engineering vs. Content Distribution: A Game Theoretic Perspective”. Department of Management Science and Engineering, Stanford University. 2009, have investigated the principle possibilities of cooperation between ISP and CDN as well as the potential of an ISP deploying its own CDN. However, even though such collaboration is discussed in theory, these studies do not propose a system that enables such collaboration, which involves complex technical hurdles in realization.
In Penno R. et al.: “ALTO and Content Delivery Networks—draft-penno-alto-cdn-02”. Cisco Systems. Oct. 25, 2010, a collaborative scheme is mentioned which requires the ISP to unveil information about its operational and topological information. However, this type of information is generally too critical for most ISP to unveil. In Contavalli C. et al.: “Client IP information in DNS requests—draft-vandergaast-edns-client-ip-01”. Internet-Draft. May 2010, the authors suggest forwarding the IP address of the client along with the DNS request. This involves substantial changes in the currently deployed DNS system and does not provide accurate information about the location of the end-user or client as well as about the network characteristics within the ISP.
Therefore, there is a need for allowing plural ISP and/or an ISP and a CDN to efficiently collaborate wherein sharing of critical information is prevented.